Originally Posted by
cblaisd
I am running into these more and more....
Example:
I've read up on them
https://en.wikipedia.org/wiki/Diverg...nd_interchange
http://www.divergingdiamond.com/
but I still don't quite get it.
The ones I've driven through lately seem to me to be slower than usual (from drivers -- like me? -- slowing down because it seems so very odd and even scary) and it appears there is no possibility that the crossing street under/over can ever NOT have a red light.
Are these really safer? Are there folks who like them? Enlighten me
You're correct that it would be rare to get through one of these intersections without a red light. A conventionally signaled intersection makes this possible at the cost of a) longer average wait times because the signals have six phases rather than two, and b) a higher theoretical accident rate.
I assume the actual accident rate for DDI's has yet to be established reliably for lack of data.
I've read that left turns across traffic (in drive-on-right countries) are the most dangerous driving maneuvers. The DDI eliminates them.
Here's a video
showing a driver navigating a DDI in Columbus, Ohio.